None of the guys share any scenes with the girls in this episode.
Professor Rothman's retirement party was already announced in The Beta Test Initiation (2012) when Kripke said that the party was moved up to next Friday.
Sheldon explains the rules of Rock-Paper-Scissors-Lizard-Spock twice. In both cases, he uses exactly the same words in the same order together with identical hand gestures. They are also exactly the same as when he explained the rules in The Lizard-Spock Expansion (2008).
While the set dressing in the bathroom scene at the university may look normal at first, the mirrors mounted on the back wall over the sinks are actually tilted downwards at a slight angle so they only reflect the bathroom floor. This was done to prevent them from reflecting the cameras & studio audience in them, which they would do if they were mounted properly.
When Sheldon is complaining about his new office you can see on the white board that he has written the notes the Chimes play and several combinations of notes the bird sings.